* packaging is required on old pythons (<= 3.7)
* pbr is required for packaging
* nvchecker was optional but new features depend on it

It's not really needed.

Add a way to specify per-project nvchecker config for upstream repos.

Individual nvchecker config files in data/upstream-nv/ must follow
naming conventions used by downstream config. When
project.upstream.nvconfig = 'foo.toml' cznicinfo uses
data/upstream-nv/foo.toml nvchecker config file to get upstream
versions.

Upstream versions are included in following commands:

* versions
* report

Refactor related code to be more universal and consistent.

It can actually render a semi-decent report now.

* new template module provides rendering of templates using jinja2

leave only selected projects in info for now.

* versions are now fetched using nvchecker
* new nv module provides utility functions for using nvchecker to check
  for new versions such as generating nvchecker config
* new cache module provides interface for accessing cache paths in
  ~/.cache/cznicinfo
* infocore was extended to support supported_distros.yaml as well as
  other arbitrary data files

License is already specified in classifier.

Use default when not provided as intended.

Clone debian package source repos from salsa.debian.org using:

        cznicinfo clone -t debian foo bar baz

This requires distro-pkgs[N].path project attribute in info which was
added for projects with debian packages.

Include util.cmd and utils.git subprocess wrappers from rdopkg for
convenient system commands interaction.

Also mention a future improvement to keeping doc text up-to-date.

Better than nothing, yes?

These fill are likely to only get bigger.

Don't load query/print code when you only want to fetch info etc.

better wait for nvchecker2 which brings support for plugins amongst
other things. It should have different config format, too.

* add datovka
* remove dns-probe
* update distro packages

and update stuff

It's not very useful by default but I still tried this so here's the
code.

until nvchecker2 comes out.

List git repos at gitlab.nic.cz in the same format `list` uses.

It's a core functionality, really.

utils module was happily obliterated.

Add basic info for following new projects:

* bird
* turris-os
* fred-server

Example of use:

    cznicinfo find -f list knot

I also cleaned up sources as flake8 commands.

Also allow dumping raw parsed project data using

    cznicinfo show --format yaml foo

Also adjust links format.

Also update cznicinfo.yaml with more information.

The journey to tame all packaging metadata begins...